# Calculating cell doubling time - (May/26/2011 )

Hi,

so I need to know how many cells I have in my wells at specific timepoints after seeding them, which means I need to know their cell doubling time. Since I work with human primary cells (HUVECs from fresh donors each time) I would have work this out myself.

I tried seeding 2 wells of 6 well plate, one with 1*10^5 cells the other with 2*10^5 cells, of each of three donors so I could combine and work out an average. But when I counted them around 18 hours later the number of cells seemed to be more or less the same in each well (Initially I thought they had doubled overnight but then I realised I had plated out 2*10^5 and 4*10^5 cells per well by mistake as I made calculation error in my dilutions)

My next plan is to seed cells at those 2 concentrations again (1*10^5 and 2*10^5 per well) but do it in more wells, then take counts at 24 hours and 48 hours. I am assuming perhaps the first day or so after seeding they just need to settle down and adhere properly before they start dividing again.

really you should do a proper growth curve - take multiple time points (i.e. more than 3, I would go for about 6-10) and use the numbers to plot a graph. You should then be able to fit a line to it which will give you an accurate representation of the doubling time.